<!DOCTYPE html>
<html lang="en">
    <head>
        <meta charset="UTF-8" />
        <meta http-equiv="X-UA-Compatible" content="IE=edge" />
        <meta name="viewport" content="width=device-width, initial-scale=1.0" />
        <title>Document</title>
    </head>
    <body>
        <pre id="box"></pre>
    </body>
    <script>
        let jsonData = [
            {
                username: 'liuhao',
                age: 18,
                sex: '男',
            },
            {
                username: 'liuhao2',
                age: 18,
                sex: '男',
            },
            {
                username: 'liuhao3',
                age: 18,
                sex: '男',
            },
        ]

        let res = JSON.stringify(jsonData, ['username', 'age'], 4)
        box.innerHTML = res
        // console.log(res)
    </script>
</html>
